xnu-6153.11.26.tar.gz

[apple/xnu.git] / bsd / man / man2 / dup.2

diff --git a/bsd/man/man2/dup.2 b/bsd/man/man2/dup.2
index c13ca0bb528a820c18c94a430779c2d4e544c0be..ec0f84d3288d1bd79af9ea5dbf676984efbfd1d3 100644 (file)
--- a/bsd/man/man2/dup.2
+++ b/bsd/man/man2/dup.2
@@ -33,7 +33,7 @@
 .\"
 .\"     @(#)dup.2      8.1 (Berkeley) 6/4/93
 .\"
-.Dd June 4, 1993
+.Dd December 1, 2010
 .Dt DUP 2
 .Os BSD 4
 .Sh NAME
@@ -52,7 +52,7 @@
 .Fa "int fildes2"
 .Fc
 .Sh DESCRIPTION
-.Fn Dup
+.Fn dup
 duplicates an existing object descriptor
 and returns its value to the calling process
 .Fa ( fildes2
@@ -100,8 +100,18 @@ In
 the value of the new descriptor
 .Fa fildes2
 is specified.
-If this descriptor is already in use,
-the descriptor is first deallocated as if a
+If
+.Fa fildes
+and
+.Fa fildes2
+are equal, then
+.Fn dup2 
+just returns
+.Fa fildes2 ;
+no other changes are made to the existing descriptor.
+Otherwise, if descriptor
+.Fa fildes2
+is already in use, it is first deallocated as if a
 .Xr close 2
 call had been done first.
 .Sh RETURN VALUES
@@ -147,7 +157,7 @@ is negative or greater than the maximum allowable number (see getdtablesize(2)).
 .Xr socket 2 ,
 .Xr socketpair 2
 .Sh STANDARDS
-.Fn Dup
+.Fn dup
 and
 .Fn dup2
 are expected to conform to